Henry c



(No Model I SERGEANT,

A DIRECT ACTING ENGINE.

No. 354,660. Patented De0.'2 1, 1886.

Ill 1 NirEn STATES HENRY C. SERGEANT, OF NEl/V YORK, N. Y.

DlRECT-ACTING ENGINE.

SPECIFICATION forming part of Letters Patent No. 354,660, dated December 21, 1886.

7 Application filed February 8, 1886. Serial No. 191,136. (No model.)

To'aZZ whom it may concern: between the chest and valve at the bottom Be it known that I, HENRY O. SERGEANT, of the city and county of New York, in the State of New York, have invented a new'and useful Improvement in Direct-Acting Engines, of which the following is a specification.

My invention relates to a rock-drill or other directacting engine, in which is employed a 'steanractuated valve that is caused to move the valve-chest is provided with ports orpassages which lead from it to the main cylinder,

and the main piston serves by its movement to place such ports or passages in communication with the atmosphere, so that whatever pressure of steam may be in the end of the valve-chest will be relieved by the placing of such end in communicationmith the atmosphere. Examples of such valves are shown in my United States Letters Patent No. 91,675, dated June 22, 1869, and No. 202,060, dated April 2, 1878. v

The invention relates more particularly to direct-acting engines in which the work is performed during the movement of the piston in one direction, the piston moving freely in the opposite or return direction. To such class of engines belong rock-drills, chipping or riveting machines, and engines for other purposes.

In the machine shown in my aforesaid Patent No. 202,060, dated April 2, 1878, there was a slide-valve formed integral with an auxiliary piston, and having a cove or cavity on the under side for placing the ports leading to the ends of the main cylinder alternately in communication with themain exhaust. The pressure with which such a valveis held to its seat, and the consequent friction opposed to its movement, renders it necessary to support the Valve on a central bolt or axial guide, as shown in said patent, and if the parts are so proportioned that the axial bolt does' support the valve there is apt to beleakage of motive fluid thereof.

One feature of 1ny"invent-i0n consists in the combination, in a direct-acting engine,with a main cylinder and a valve-chest provided at the ends of said chest with pairs of passages, one passage of each pair leading from the end of the valvechest to the cylinder, and the other of each pair leading from the cylinder to the atmosphere, of a free-running balanced piston-valve which is caused to move by pressure on one end when the other end of its valvechest is placed in communication with the atmosphere, and a main piston grooved circumferentiall y, and serving by its movement to establish communication between the opposite ends of the valve-chest and the atmosphere, whereby the ends of the valve'chest will be alternately relieved of pressure.

In a rock-drill, to perform the best work, it is necessary that the drill should strike the rock with full force, and without the piston being cushioned by steam or motive fluid, and if the valve be shifted to admit steam to the lower or forward end of the cylinder in front of the piston too soon before the completion of itsworking stroke the striking force of the drill or bit will be greatly reduced. It is also necessary in such a' machine that the valve should be shifted to admit motive fluid to the upper or rear end of the cylinder before the piston has completed its upward or return stroke, and in order to prevent the piston from knocking the back head out.

\ Attempts have been made to secure the desired results by giving the steam-actuated valve a sluggish movement due to friction or to the reduction of the size of the passages or ports which extend from the valve-chest to the main cylinder, and which are controlled by the moving piston; but the results have not been satisfactory and the valve has been liable to shift, so as to cushion the piston in its working stroke, or has been liable to delay its movement to such an extent as to cause the that a valve which operates so as to prevent the piston from striking the rear head when drilling downward and when the weight of the piston is against its upward movement will not prevent the piston from striking the rear head when the drill is used in heading-work or drilling upward, and when the weight of the piston aids its return.

A further object of my invention is to provide a valve which is preferably balanced so as to move freely in either direction, and which, while it will not cushion the piston in its working stroke, will prevent the piston from knocking out the rear head; also to provide convenient means of adj ustment,whereby such valve may be adapted to properly control the'rearward or return stroke of the piston when the drill is operated in its various positions, either working downward, horizontally, or upward.

In machines having valves of the class to which my invention relates the main cylinder is provided, as above described,with passages or ports which extend to the opposite ends of the valve-chest, and with companion passages leading to the atmosphere, and the main piston has-a" circumferential groove or channel,

by which these ports or passages are placed in communication, in order to reduce the pressure first on one and then on the other end of the valve. I have discovered thatby making the passage or port leading from the rear end of the valve-chest to the main cylinder elongated in the direction of the length of the cylinder a better operation of the machine will be secured. This elongated passage or port I preferably make in the form of two or more holes or ducts, which are arranged one behind auotherlengthwise of the cylinder, but one or more of which may be stopped up or closed, according to whether the machine be working downward, horizontally, or upward.

The invention consists in novel combinations of parts,which are hereinafter described, and pointed out in the claims.

In the accompanying drawings, Figure 1 is a longitudinal or axial section of such parts of a rock-drill as are necessary to illustrate my invention. Fig. 2 is a transverse section thereof on the plane of the dottedline x m, Fig. 1. Fig. 3 is a horizontal section through the valve-chest on the plane of the dotted line y Fig. 1; and Fig. 4 is a plan of. the cylinder, the valve-chest being removed therefrom.

Similar letters of reference designate corresponding parts in all the figures.

A designates the main cylinder, and B the piston, which is fitted to reciprocate therein, and to. the piston-rod B of which the drill or bit is to be secured. The cylinder is to be provided at the ends with suitable heads, which I will not describe,- as they form no part of my invention, and the piston is provided with suitable rotating devices, which I have not shown, as they also are notincluded in my invention. The piston is provided with suitable ring-packing, b, and it has a circumferential groove or channel, B, whereby the opposite esaso ends of the valve-chest are alternately placed in communication wit-h the main exhaust and with the atmosphere, as is usual in machines valve, D. The opposite ends of the valvechest 0 are closed by heads 0, secured by bolts 0 thereto, and the valve D is cushioned at opposite ends of its stroke by india-rubber buffers O", or other springs secured in the ends of the valve-chest and faced with a metal plate, 0', as shown in Figs. 1 and 3.

The cylinder is provided with a main exhaust port or passage, (1, and with ports or passages d (P, which lead to opposite ends of the cylinder A, and which serve both for the supply of motive fluid to and its exhaust from the ends of the cylinder. The ends ofthe pas sages d d which communicate with the cylinder may consist of openings or holes (1*, arranged side by side in a direct-ion circumferential to the cylinder, as shown in Fig. 4 by dotted lines, so that the packing-rings of' the piston will not be liable to slip into or be cut by these passages, as they might bein case the cylinder end of each passage (1 d were made in the form of a single slot of considerable length circumferential to the cylinder. In the valve-chest are formed an exhaust port, 0, which is continued in a circumferential groove in the interior surface of the chest, and ports 0 6 which are also continued in circumferential grooves in theinterior surface of the chest. In opposite sides of the chest are sup pl y-openwhich passagesf lead to the bore of the chest,

and are continued therein in circumferential grooves.

The balanced piston-valve D has two circumferential grooves or channels, 9 g, and it will be understood that by'moving this valve in one or other direction the passages ee will be brought alternately into communication with the exhaust passage or port 6, and with the supply passage or port f. It is not intended to. introduce steam or other motive fluid into both sides of the valve-chest, but only into one side thereof, and the other inletopening or pipe socket, f, may be plugged up, as shown in Figs. 2 and 3. i

In order that the movements of the valve D may be properly controlled by the main piston B, the main cylinder should communicate with the valve-chest and with the atmosphere or main exhaust at opposite each end of the chest, and the cylinder upon the side of the exhaust d is provided with a cavity or internal exhaust-chamber, d". (Shown by dotted lines in Fig. 1 and in Fig. 2.) The lower end of the valve-chestCcommunicates with the main cylinderby a port or passage, awhich leads from the main cylinderto arecess, j, formed between the valve-chest and the main cylinder, and a duct or opening, 13*,formingapart of said pas- IIQ IIS

sage or port, and leading from said recess to the lower end of the valve-chest. The main cy1- inder A also has in the same circumferential plane with the passage or port t a passage or port, is, leading into the exhaustchamber (P, and it follows that whenever the circumferential groove B of the piston places the ports or passages t k in communication the pressure in theleft-hand end of the valve-chest G will be reduced or exhausted to the atmosphere, and the valve D will be thrown over in that direction by the motive fluid pressing against its opposite end.

At the right-hand or upper end of the valvechest 0, I have shown a passage or port which is, as here represented, composed of three holes or ducts, 2'', arranged one behind another lengthwise of the cylinder, and communicating with the'right-hand end of the valve-chest through a recess, j, formed between the valvechest and the cylinder, and a duct or opening, 2', leading from said recess to the end of the valve-chest G. In planes circumferential to the cylinder and coincident with the three holes or ducts 'i' are other holes or ducts, i leading to the exhaust-chamber d and through it to the atmosphere, and it will be understood that as the piston B makes its stroke the holes or ducts t" are, through the circumferential channel B of the piston B, successively placed in communication with the holes or ducts i, and through them with the atmosphere.

In constructing a drill I may provide any desired nu mber of holes or ducts i, greater or less tlianthree, as in some cases two ducts might be desirable, and in others four, or even more. In Fig. 1 of the drawings I have represented the piston B at the right-hand or up-; per end of the stroke. During the movement o f the piston toward the right or upward, the ducts or holes t" were placed in communication with the atmosphere through the holes or ducts i", and the pressure in the righthand end of the valve-chest G was reduced to such an extent that the valve was thrown over toward the right by the pressure on its opposite or left-hand end; and by such movement of the valve the ports or passages e (2 leading to the upper or rear end of the cylinder, were placed in communication with the supply-.

port f.

WVith a free-moving balanced valve the valve will be shifted to the right as soon as the first of the holes or ducts i is placed in communication with the atmosphere by the channel or groove B of the piston, and it will therefore be understood that the rearward or return stroke of the piston will be limited by the open only the duct or hole t" which is nearest the upper end of the cylinder, and in that case the valve will not be shifted to admit motive fluid above the piston until the piston has very nearly completed its return or upward movement. In case the machine is used for heading-work, in drilling horizontally or upward, the weight of the piston will be neutral, or will tend to accelerate or assist the return or rearward movement of the piston, and it will therefore be necessary to shift the valve earlier in the return-stroke of the piston, and when it is at some distance from the rear head of the cylinder. For such use of the drill the plugs Zmay be removed from one or both of the holes or ducts i, and the motive fluid will be admitted behind the piston in time to pre vent its striking and knocking out the rear head of the cylinder.

The insertion or removal of the plugsl from the holes or ducts t" is a very simple matter,

it being only necessary to unbolt the valvechest'O from the cylinder; and by this simple means I provide for performing the best work by the machine, whatever he the position in which it is used, and prevent the rear head of the cylinder from being knocked out by the piston. When the machine is new and all the parts are tightly fitting and do not move as readily as they will after the machine has been run for a little time, it may be desirable to place the valve-chest in communication with the atmosphere later in the stroke of the piston, to insure the shifting of the valve at the most desirable time, and the series of holes or duct-s a" and the plugs fitted thereto afford convenient provision for adjustment to suit such varying' conditions of the machine.

.It will be seen that by the arrangement of the holes or ducts 2" one behind anotherlengthwise of the cylinder the length of the piston from the groove B to the lower end has been very materially increased from what is possible with a single duct or passage only, as is usually employed. As the valve is shifted to admit motive fluid below the piston, as soon as the lower end of the groove B comes to the ducts or passagest'k, the increase in the length of the piston below said groove causes the valve to be held back before shifting when the piston is moving toward the roclg and prevents the shifting of the valve too soon to ob tain the most effective result.

It will be seen that the two or more holes or ducts i, which are arranged in line, or one behind another, lengthwise of the cylinder, form in effect a passage or port which is elongated in the direction of the length of the cylinder. A similar series of holes or ducts, z" i may be provided at the other end of the valve-chest, in lieu of the single ducts, passages, or portst' k,

I am aware of Letters Patent No. 252,920,

granted January 31, 1882, to Allen, and do not desire to include in my invention the engine shown therein. In that engine the main piston is hollow, so that the motive fluid may pass from the upper end of the main cylinder directly downward into the piston, and said main piston has openings extending from its interior cavity to its circumference, and when by the movement of the piston these openings or holes pass the passages which lead to the end of the valve-chest the motive fluid under pressure will pass through the piston and through the passages into the end of the valvechest and will effect the movement of the valve. In my machine the piston serves by its movement to place the holes or ducts i in com mu nication with the atmosphere through the passages i and by so placing said holes or ducts in communication with the atmosphere the pressure in the end of the valve-chest is relieved, and the valve will be shifted bythe pressure on its opposite end.

What I claim as my invention, and desire.to secure by Letters Patent, is-

1. In a direct-acting engine, the combination, with a main cylinder and a valve-chest provided at the ends of said chest with pairs of passages, one passage of each pair leading from the end of the valve-chest to the cylinder, and the other passage of each pair leading from the cylinder to the atmosphere, of a free-running balanced piston-valve which is caused to move by pressure on one end when the other end of its valve-chest is placed in communication with the atmosphere, and a main piston grooved circnmfcrentially, and

serving by its movement to establish communication between the opposite ends of the valve-chest and the atmosphere, whereby the ends of the valve will be alternately relieved whereby the portion of the piston below the groove may be lengthened-without destroying proper communication with the valve-chest, substantially as herein described.

3. The combination, with a balanced pistonvalve which is caused to move by pressure upon its end, of a main cylinder having its passage or port which leads to the end of the valve-chest elongated in the direction of the length of the cylinder, and a main piston, by

the movement of which the said elongated passage or port is placed in communication with the atmosphere, substantially as herein described.

4. The combination, with a steam-actuated valve which is caused to move by pressure on its end, of a main cylinder communicating wit-h the end of the valve-chest by a der having two or more holes or ducts, 6',

through which it communicates with the end of the valvechest, and a main piston, by the movement of which said holes or ducts will be successively placed in communication with the atmosphere, substantially as herein described.

6. The combination, with the balanced piston-valve D and its chest 0, having between it and the cylinder the recess or cavity j, which communicates by the duct '17 with the end of thevalve-chest, and bythe two or more ducts i i with the main cylinder, of the main piston, by the movement of which the ducts i will be successively placed in communication with the atmosphere, substantially as herein described.

HENRY O. SERGEANT. Witnesses:

FREDK. HAYNEs, HENRY MCBRIDE. 

